1. Field of the Invention
This invention concerns fluid flow measurement, in general. More specifically, it relates to a multi-phase flow meter that is applicable to a fluid that includes both liquid and gas components therein.
2. Description of the Prior Art
Heretofore there have been various suggestions for measuring fluids having more than one phase component, but such phases were both liquids. There has historically been a major problem in measuring flow rates of a mixture including gas as well as liquid because the flow rates of these two components have a great tendency to be different. Consequently, in the petroleum industry it has been the practice to have a test separator at a crude oil collection point for making individual flow measurements of the gas and liquid. Such procedure could be eliminated by use of a continuous flow multi-phase meter for both liquid and gas according to this invention.
Examples of prior meter structures for measuring flow rate of multi-phase fluids that only are applicable to liquid phases are the two U.S. Pat. Nos. 2,936,618 to H. S. Milam, May 17, 1960 and 3,304,766 to L. M. Hubby, Feb. 21, 1967. It may be noted that the Milam patent makes cyclic measurements of the quantity of water in a fluid mixture of oil and water, while the Hubby patent measures the thermal capacity of the mixed fluid in order to determine the constituent amounts of oil and water in the mixture. Neither of these patents makes provision for measuring the rate of flow of a gas which might be included in a fluid mixture.
Consequently, it is an object of this invention to provide a fluid flow meter that makes positive displacement measurements which maintain the volume flow rate of a mixed fluid while maintaining the linear velocity of the liquid and gas components thereof the same.